--******************************************************************************
--*                                                                            *
--*  File:        IntegerDomain.lua                     Revision:  1.0         *
--*                                                                            *
--*  Purpose:     determines the range of integer values Lua is able to repre- *
--*               sent exactly(!)                                              *
--*                                                                            *
--*  Creation:    14.11.2004                   Last Modification:  14.11.2004  *
--*                                                                            *
--*  Environment: Lua 5.0, LuaJava 1.0b3, Java 1.4.2                           *
--*                                                                            *
--*  Author:      Andreas Rozek           Phone:  ++49 (7031) 222305           *
--*               Bunsenstraße 80/1       Fax:    -                            *
--*             D-71032 Böblingen         EMail:  Info@Andreas-Rozek.De        *
--*               Germany                                                      *
--*                                                                            *
--*  URL:         http://www.Andreas-Rozek.de/                                 *
--*                                                                            *
--*  Copyright:   the software is published under the "GNU Lesser General Pub- *
--*               lic  License" (see "http://www.fsf.org/copyleft/lesser.html" *
--*               for additional information)                                  *
--*                                                                            *
--*  Comments:    this script was originally written using Lua 4.0 and then    *
--*               converted to Lua 5.0                                         *
--*                                                                            *
--******************************************************************************

  println();
  println("IntegerDomain - what is the largest supported integer number?");
  println();

  local Step = 2;
  while (true) do
    local nextStep = Step*2;
    if (math.floor(nextStep) == nextStep) and (nextStep-1 ~= nextStep) then
      Step = nextStep;
    else
      break;
    end;
  end;

  local Limit,Step = Step,Step/2;
  while (Step > 0) do
    local nextLimit = Limit+Step;
    if (math.floor(nextLimit) == nextLimit) and (nextLimit-1 ~= nextLimit) then
      Limit = nextLimit;
    end;

    Step = math.floor(Step/2);
  end;

--local printableLimit = string.format("%d", Limit);         -- fails under Lua!
  local printableLimit = string.format("%.16e", Limit);

  println("supported integer range is: -"..printableLimit.."...+"..printableLimit);